Explain the term "cardiac output."

Cardiac output is defined as the volume of blood ejected by the heart per minute, which is a critical measure of heart function and circulatory efficiency. This parameter is vital for maintaining adequate blood flow to meet the body's metabolic needs. It is influenced by two main factors: heart rate, which is the number of beats per minute, and stroke volume, which is the amount of blood pumped with each heartbeat. The product of these two factors provides a comprehensive picture of cardiac performance; thus, an increase in either heart rate or stroke volume will lead to an increase in cardiac output.

Understanding cardiac output is essential for assessing cardiovascular health, as it helps in diagnosing conditions such as heart failure, where the heart is unable to pump blood effectively, leading to decreased output and insufficient blood flow to organs and tissues.